Arduino Pulse counting from energy meter vs current sensor method?



  • Re: [contest] My 12 input high precision pulse counter (kWh/ W)

    Hello guys i want to do a system for my home where i can monitor energy either from energy meter pulse output (SDM72DR) or using current transformer arduino sensor and displaying the cost of kwh used in a serial monitor, which one would be reliable and provide accurate information,i had about 17000/- RS last months bill due to more energy consumption by family members, i believe if i put up such a system of showing amount used,i hope they might be careful on energy consumption like not wasting or not using unless they need, i came through lot of projects here but to be honest i have "0" knowledge about arduino! am not a engineer, but i can learn if any one tries to teach me and however this will be my first project, i just want to know what all things need to bought to do this project successfully and most importantly how can i learn the coding part, pls help me ..thank you!


  • Hero Member

    @ragaven From the perspective of a starter. ... If you already have the SDM72DR, it has a display, so would give you basic information on energy usage. From there you can start to build your first simple energy pulse counting project to read and display and log information on a controller.

    Current transformers are easier to install on the high voltage side but are more difficult to handle on the low voltage side and (little) less accurate. If you have a 3-phase installation (SDM72DR is 3 phase) then you would need 3 current transformers and interpret their output..

    I am the author of the project you are referencing and I would not recommend to make this your first. It is rather extensive (master/slave arduino's/ local display/ rotary encoder...)



  • @AWI thank you for replying, firstly it is your project that inspired me to build one, and regarding Current transformer i already have 3 ct coils with ratios 100/5 in line with the energy meter, am using those CT's for selec multination meter [mfm384] as SDM72DR doesn't support monitoring electrical parameters! installing too many ct's might be a messy inside my electrical panel box, so that is why am thinking of pulse counting and my home is 3 phase system and for testing purpose alone i also got SDM120 D(A) ,which has also pulse outputs so i can wire to my project and play with it !from your project i have bought

    UNO r3 -1
    arduino pro mini 5v 16M -1
    i2c lcd 16x2 -1
    rotatry decoder/encoder -1
    some assorted mini components!!

    so i can programe my uno to be master and micro to be slave and read output? what are your thoughts AWI ?


  • Hero Member

    @ragaven So you decided to take a big leap! that's one way to learn how to swim ;-)

    Your shopping list sounds good. I would advise to build and test the slave first ..



  • @AWI am curious to learn i just cant wait to receive the items ive ordered,but also terrified as u said am taking a big leap :O !



  • @AWI you were right about using CT's as they are easy and reliable, after researching for several hours,i found that pulse counting is not reliable as there would be low counts during less energy being used and those missed pulse would not provide accurate output, so i decided to go with CT itself, at first i did not know there was specific CT's for used with arduino, i was thinking of conventional CT (tape wound) which is very big and heavy, but now after seeing Non-invasive CT [SCT-013-000 ] at aliexpress , am thinking its very very easy to install as it is also split core and from here i found this link text which will be compatible to CT am buying now can i get desired result from Emontx shield and arduino uno r3 to display KWH used and cost of usage on my serial display? but there is also an decription that says [EmonTx Arduino shield is not compatible with other Arduino shields that use I2C] i dnt understand what it means and am not intending to upload anything in web (emoncms)...is this better idea than pulse counting? what are your thoughts AWI?


  • Hero Member

    @ragaven depending on you perspective. Pulse counting is very reliable. The area in which it gets complicated is where you have a low energy consumption. In that situation the time between the pulses can be long. Actual current energy is calculated by using time between pulses.
    In practice most pulse meter have a 1 watt pulse. So with a 60 watts consumption there is one pulse per minute which is sufficient for me.
    Accuracy of usage (kWh) is very high. My meters are on par (within 10Wh) with the actual consumption after 6 months.



  • @AWI the meter am getting has 1000 impulse /kwh so if am consuming 1000 watts there would be approx.16 pulses evry minute, and increases as kwh gets higher?


  • Hero Member

    @ragaven That's right. So with a consumption of 1.000 watts you will be able to update the consumption rate 16 times per minute. Pretty accurate ...



  • @AWI from your tutorial i understand your creating pulses every 10 sec right? now those pulse goes into energy meter and comes out depending on the kwh usage and you have an another arduino setup to read/sense those output right? my doubt is why do you want to create pulse when there is already a pulse creating relay is inside the meter(which is normally open?) so you can simply apply constant voltage and the kwh meter would close circuit and open as per usage which is created as pulse? and you said that we actually count time taken between pulses is used for determining the KW used so in my case there's approximately 3.75 seconds between each pulse for 1kwh, why dnt we count no of pulse instead of counting time interval between pulse?



  • @AWI i have received two modules today pro microi2c lcd the arduino-pro-mini doesnt have usb input,how do i upload sketches to it ,do i need a special usb cable for it?


  • Hero Member

    @ragaven you will need a Ftdi adapter or clone to program the mini.



  • @AWI The ftdi Adapter was priced at the range of an uno r3 board,so i bought an uno r3 board itself and i tested the output pulse from the multifunction meter today all is working well except,i did not use Arduino power,i used 24vdc as said in the manual to check everything is good and output pulse made few led's to blink for 2 sec alt text and there is an option for pulse timing on the meter! am bit worried abt the connections to be made with arduino as i have no idea which goes where :(



  • @AWI i have finished connecting master and slave arduino based on your method(posted images) i havent run the code to test, can you pls check and tell if my connections are correct, i have also designed in autodesk circuits, but due to lack of some components like i2c adapter and rotarty encoder & kwh meter, i have substituted ones looking like them,the wiring color red is for + and black is for "- ", dt,clk,sda,scl are color coded and wired as your image, its only for connection checking purpose....pls check autodesk circuits thank you!


  • Mod

    Have you finished your project?



  • @gohan yes its almost complete, since i ran out of memory in UNO. Am waiting to get mega and it will be all over soon. ...


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